Auto-adjusting mask stabilizer

ABSTRACT

A forehead support for a facial mask is adapted to be moveable between a first position with respect to a frame of the mask and a second position with respect to the frame. The forehead support includes a biasing mechanism that urges the forehead support in the second position. A method of positioning a forehead support with respect to a frame of a patient interface includes positioning the forehead support and patient interface assembly on a face; disengaging a forehead support locking mechanism; allowing the forehead support to move from a first position to a second position; and engaging a forehead support locking mechanism.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.12/134,871, filed Jun. 6, 2008, now allowed, which claims priority toU.S. Provisional Application 60/945,380, filed Jun. 21, 2007, each ofwhich is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

Sample embodiments of the present invention relates to an automaticallyadjusting mask stabilizer for a facial mask used to supply breathablegas to a wearer's airways.

Sample embodiments of the invention have been developed primarily foruse in supporting a mask used in Continuous Positive Airway Pressure(CPAP) treatment of, for example, Obstructive Sleep Apnea (OSA) andother ventilatory assistance treatments such as Non-Invasive PositivePressure Ventilation (NIPPV) and will be described hereinafter withreference to this application. However, it will be appreciated that thesample embodiments of the invention are not limited to these particularuses and are also suitable for use with, for example, nasal (nose only),mouth only, or full-face (i.e. nose and mouth) masks, or prongs,nozzles, puffs or the like.

BACKGROUND OF THE INVENTION

CPAP treatment is a common ameliorative treatment for breathingdisorders including OSA. CPAP treatment, as described in U.S. Pat. No.4,944,310, provides pressurized air or other breathable gas to theentrance of a patient's airways at a pressure elevated above atmosphericpressure, typically in the range 4-20 cm H₂O.

It is also known for the level of treatment pressure to vary during aperiod of treatment in accordance with patient need, that form of CPAPbeing known as automatically adjusting nasal CPAP treatment, asdescribed in U.S. Pat. No. 5,245,995.

NIPPV is another form of treatment for breathing disorders which caninvolve a relatively higher pressure of gas being provided in thepatient mask during the inspiratory phase of respiration and arelatively lower pressure or atmospheric pressure being provided in thepatient mask during the expiratory phase of respiration.

In other NIPPV modes the pressure can be made to vary in a complexmanner throughout the respiratory cycle. For example, the pressure atthe mask during inspiration or expiration can be varied through theperiod of treatment.

Typically, the ventilatory assistance for CPAP or NIPPV treatment isdelivered to the patient by way of a nasal mask. Alternatively, a mouthmask or full face mask or nasal prongs can be used. In thisspecification any reference to a mask is to be understood asincorporating a reference to a nasal mask, mouth mask, full face mask ornasal prongs.

In this specification any reference to CPAP treatment is to beunderstood as embracing all of the above described forms of ventilatorytreatment or assistance.

A CPAP apparatus broadly comprises a flow generator constituted by acontinuous source of air or other breathable gas such as a hospitalpiped supply or a blower. In the latter case, an electric motor drivesthe blower and is typically controlled by a servo-controller under thecontrol of a microcontroller unit. In either case, the gas supply isconnected to a conduit or tube which in turn is connected to a patientnasal or full-face mask which incorporates, or has in close proximity,an exhaust to atmosphere for venting exhaled gases. Examples of priorart nasal masks are shown in U.S. Pat. Nos. 4,782,832 and 5,243,971.

The supply conduit delivers gas into a chamber formed by walls of themask. The mask is normally secured to the wearer's head by straps. Thestraps are adjusted to pull the mask against the face with sufficientforce to achieve a gas tight seal between the mask and the wearer'sface.

A problem that arises with the use of the existing masks is that inorder for the straps to be tight, the mask is compressed against thewearer's face and may push unduly hard on the wearer's nose or face.Additionally, the mask may move around the wearer's face. Thus, therehas been hitherto provided a stabilizing support, such as a foreheadsupport, which provides a support mechanism between the mask and theforehead. This forehead support prevents both the mask from pushing toostrongly against the wearer's nose and/or facial region (by distributingforces) as well as minimizing movement of the mask with the addition ofa contact point between the mask and the wearer's head thereby reducinguncomfortable pressure points. Additionally, the forehead support can bearranged to prevent the gas supply conduit from contacting the wearer'sforehead or face.

In order to fit a mask system to a patient, the cushion is fitted to theface of the patient and an ideal position is found. The ideal positionis one in which a good seal is formed and the mask feels comfortable tothe patient. Once the ideal position is found, the forehead support isbrought into contact with the patient's head to provide stability to theideal position of the mask relative to the patient's head.

Another problem that arises with the use of existing masks is that manyforehead supports require two hands to adjust. One hand is typicallyused to secure the mask, while the other hand is used to adjust theposition of the forehead support. Such an adjustment may require toohigh a level of dexterity for some patients or clinicians. In addition,existing mask systems provide discrete adjustment points for theposition of the forehead support, leading to a trial and error processin determining the ideal position. It is also difficult to determine howmany discrete positions should be provided. If too few discretepositions are provided, it may not be able to set or lock the foreheadsupport in a position that truly stabilizes the mask in the idealposition. If too many discrete positions are provided, the fitting maybe complicated by the patient being unable to decide which positionstabilizes the mask in the ideal position.

An even further problem with the use of existing masks is that theadjustment of the forehead support changes the inclination between theforehead support pads and the patient's forehead. For example, theforehead support shown in U.S. Pat. No. 6,532,961 includes a frame thatis movably (e.g. pivotably) adjustable with respect to the mask.Pivoting of the forehead support during the adjustment process changesthe inclination between the pad and the patient's forehead and mayresult in an undesirable change in the amount of support provided by theforehead support.

Thus, a need has developed in the art to address one or more of theabove problems.

SUMMARY OF THE INVENTION

One aspect of the invention relates to an auto-adjusting mask stabilizerthat permits automatic and/or semi-automatic adjustment of a stabilizer(e.g., a forehead support or facial support) for a mask with a minimallevel of dexterity and in a shorter amount of time than is currentlypossible.

Another aspect of the invention relates to an auto-adjusting maskstabilizer that has fewer parts, is less complex, and is of reducedoverall dimensions than currently available stabilizers and/or supports.

Still another aspect of the present invention relates to anauto-adjusting mask stabilizer that permits the determination of theideal mask position, based on comfort and seal, and securement of theideal position in a shorter amount of time and with less effort than iscurrently possible.

Yet another aspect of the present invention relates to an auto-adjustingmask stabilizer that may be operated with one hand.

An even further aspect of the present invention relates to anauto-adjusting mask stabilizer that maintains an angle of inclinationbetween the stabilizer and the patient's forehead regardless of therelative position of the stabilizer to the mask.

Another aspect of the present invention relates to an auto-adjustingmask stabilizer that permits the mask stabilizer to be locked in aplurality of positions, including in continuously variable positions.

According to one embodiment of the invention, a forehead support for afacial mask is provided. The mask includes a frame, and the foreheadsupport is adapted to be moveable between a first position with respectto the frame and a second position with respect to the frame. Theforehead support comprises a biasing mechanism that urges the foreheadsupport in the second position.

According to another embodiment of the invention, a mask assemblycomprises a frame, a forehead support, and a spring mechanism. Theforehead support is free to move between a first position and a secondposition and the spring mechanism is arranged to direct the foreheadsupport to the second position.

According to still another embodiment of the invention, a stabilizer fora patient interface is provided. The patient interface includes a frame,and the stabilizer is adapted to be moveable between a first positionwith respect to the frame and a second position with respect to theframe. The stabilizer comprises a biasing mechanism that urges thestabilizer into the second position.

According to a further embodiment of the invention, a method ofpositioning a forehead support with respect to a frame of a patientinterface is provided. The method comprises (i) positioning the foreheadsupport and patient interface assembly on a face; (ii) disengaging aforehead support locking mechanism; (iii) allowing the forehead supportto move from a first position to a second position; and (iv) engaging aforehead support locking mechanism.

According to yet another embodiment of the invention, a mask assemblycomprises a mask frame; a cushion attached to the frame and adapted tocontact the face of a patient in a substantially airtight manner; and astabilizer element connected to and translatably movable with respect tothe mask frame. An inclination angle between the stabilizer element andthe mask frame remains constant as the stabilizer translates withrespect to the frame.

According to an even further embodiment of the invention, a method offitting a mask assembly to a patient's face is provided. The maskassembly comprises a mask frame, a cushion attached to the mask frame, astabilizer element supported by the mask frame for translation withrespect to the mask frame, a biasing element that biases the stabilizerelement with respect to the mask frame, and a lock mechanism that locksthe stabilizer element at a position relative to the mask frame againstthe bias of the biasing element. The method comprises placing thecushion against the patient's face to establish a substantially airtightseal at a first comfortable position; unlocking the lock mechanism topermit the biasing element to bias the stabilizer element against thepatient's face when the cushion is in the first comfortable position;and locking the lock mechanism to lock the stabilizer element andstabilize the cushion at the first comfortable position.

According to another embodiment of the invention, a stabilizer for amask assembly comprises a mask frame extension adapted to be connectedto a mask frame of the mask assembly; a pad support element translatablysupported by the mask frame extension, the pad support element beingconfigured to support a pad that, in use, contacts a face, e.g. cheeksor upper lip, of a wearer of the mask assembly; and a biasing elementthat biases the stabilizer with respect to the mask frame extension.

Other aspects, features, and advantages of this invention will becomeapparent from the following detailed description when taken inconjunction with the accompanying drawings, which are a part of thisdisclosure and which illustrate, by way of example, principles of thisinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings facilitate an understanding of the variousembodiments of this invention. In such drawings:

FIG. 1 is a perspective view of a mask including an auto-adjusting maskstabilizer according to one embodiment of the invention;

FIG. 2 is a perspective view of an auto-adjusting mask stabilizer ofFIG. 1;

FIG. 3 is a perspective view of a cushion frame of an auto-adjustingmask stabilizer of FIG. 1;

FIG. 4 is a perspective view of a mask extension of an auto-adjustingmask stabilizer of FIG. 1;

FIG. 5 is a perspective assembly view of the mask extension and cushionframe of the auto-adjusting mask stabilizer of FIG. 1;

FIG. 6 is a front side perspective view of the mask extension andcushion frame of the auto-adjusting mask stabilizer of FIG. 1;

FIG. 7 is a rear side perspective view of the mask extension and cushionframe of the auto-adjusting mask stabilizer of FIG. 1;

FIG. 8 is a perspective view of an auto-adjusting mask stabilizeraccording to another embodiment of the invention;

FIG. 9 is an elevation view of an auto-adjusting mask stabilizeraccording to another embodiment of the invention;

FIG. 10 is an elevation view of an lock release mechanism for theauto-adjusting mask stabilizer of FIG. 9;

FIGS. 11 and 12 are elevation views of an embodiment of a lock releasemechanism for an auto-adjusting mask stabilizer according to theinvention;

FIG. 13 is an illustration of an auto-adjusting mask stabilizeraccording to another embodiment of the invention; and

FIGS. 14 and 15 are sectional views of an auto-adjusting mask stabilizeraccording to another embodiment of the invention.

DETAILED DESCRIPTION

The following description is provided in relation to several embodimentswhich may share common characteristics and features. It is to beunderstood that one or more features of any one embodiment may becombinable with one or more features of the other embodiments. Inaddition, any single feature or combination of features in any of theembodiments may constitute additional embodiments.

In this specification, the word “comprising” is to be understood in its“open” sense, that is, in the sense of “including”, and thus not limitedto its “closed” sense, that is the sense of “consisting only of”. Acorresponding meaning is to be attributed to the corresponding words“comprise”, “comprised” and “comprises” where they appear.

The term “air” will be taken to include breathable gases, for exampleair with supplemental oxygen. It is also acknowledged that the blowersdescribed herein may be designed to pump fluids other than air.

FIRST EMBODIMENT

Referring to FIG. 1, an auto-adjusting mask stabilizer, e.g., foreheadsupport, 10 according to one embodiment of the invention includes acushion frame 12 mounted to a frame extension 14. The frame extension 14is connected to, or formed integrally with, a mask 16 used to supplybreathable gas to a patient. A separate frame extension allows theauto-adjusting mask stabilizer of the present invention to be adapted toexisting mask frames.

The mask 16 includes a mask frame 17 and a mask cushion 19. The maskframe 17 includes an angled connector 18 (e.g., in the form of a swivelelbow) which has a distal end 20 for connection to a gas supply hose(not shown) and a proximal end 22 for connection to the mask 16. Theconnector 18 communicates the supplied gas from the gas supply hose tothe interior of the mask 16. The mask frame 17 also includes a pair ofslotted connectors 24 to which are respectively connected ends of alower head strap (not shown) for securing the mask 16 to the patient'shead.

The frame extension 14 is provided on top of the mask frame 17 generallyadjacent and above the patient's nose. It should be appreciated that themask 16 shown in FIG. 1 is just one example of a respiratory mask thatmay be supported by the mask stabilizer 10. For example, the maskstabilizer 10 may also be used in supporting a nasal mask, a full-face(i.e. nose and mouth) mask, or nasal prongs, puffs, nozzles or the like.

The mask stabilizer 10 may also be used with facial masks in which theangled connector 18 is incorporated into the mask in the generalposition of the frame extension 14. In this type of mask, the suppliedgas flows through or past the mask stabilizer 10.

The cushion frame 12 includes a pair of cushions (e.g., foreheadcushions) 25 mounted at each end of the upper portion of the frame 12 onthe side adapted to contact the face of the patient (e.g., the patient'sforehead). Examples of cushions 25 include open or closed cell foam,silicone, dual durometer foams, single pads or multiple pads joinedtogether. The cushions 25 may be integrally molded with the cushionframe 12 or attached thereto by clips or adhesives or the like. Thecushion frame 12 also includes slotted connectors 26 adjacent each ofthe cushions 25 to which are respectively connected ends of an upperhead strap (not shown) for securing the mask 16, including the maskstabilizer 10, to the patient's head.

Referring to FIGS. 2 and 4, the frame extension 14 includes a frameextension cylinder 30. As shown in FIG. 4, the frame extension cylinder30 includes a bore 36. A cantilevered lever 34 is formed in an outerperipheral surface of the frame extension cylinder 30. A lock mechanismrelease button 32 is provided on the free end of the lever 34.

As shown in FIGS. 2 and 4, the cushion frame 12 includes a shaft 40 thatis received in the bore 36 of the frame extension cylinder 30.

Referring to FIG. 3, the shaft 40 is also in the form of a cylinder. Abiasing element 42, e.g. a compression coil spring, is provided insidethe shaft 40. The biasing element 42 may be secured to the cushion frame12 at the end of the shaft, i.e., on the portion of the cushion frame 12that supports the cushions 25. Referring again to FIG. 1, it should alsobe appreciated that the mask stabilizer 10 may be adjusted to controlthe deflection of the mask cushion 19, for example in the region of thepatient's nasal bridge.

Referring to FIG. 4, the frame extension cylinder 30 includes radialprojections 38 on the inner cylindrical surface of the cylinder 30. Theradial projections 38 extend axially along the cylinder 30. As shown inFIG. 5, the radial projections 38 are received in radial grooves 44formed in the outer circumferential surface of the shaft 40 of thecushion frame 12. Although the frame extension cylinder 30 and the shaft40 of the cushion frame 12 are shown having circular cross-sections, itshould be appreciated that the cylinder and shaft may have a polygonalcross-section, for example.

As shown in FIG. 4, the lock mechanism release button 32 has a pawl 50which extends from the release button 32 radially inward of the frameextension cylinder 30. The pawl 50 has ratchet teeth 52 provided onopposite sides. The pawl 50 and the release button 32 are resilientlysupported at the end of the cantilevered lever 34.

Referring to FIG. 5, the shaft 40 of the cushion frame 12 includes anaxial slot 45. The slot 45 includes ratchet teeth 46 on each side. Whenthe shaft 40 of the cushion frame 12 is inserted into the bore 36 of theframe extension cylinder 30, the pawl 50 of the lock release button 32is received in the axial slot 45 of the shaft 40 so that the ratchetteeth 52 of the pawl 50 engage the ratchet teeth 46 of the axial slot45. The engagement of the radial projections 38 of the frame extensioncylinder 30 into the radial grooves 44 of the shaft 40 of the cushionframe 12 ensure that the cushion frame 12 and the frame extensioncylinder 30 are properly aligned for assembly of the mask stabilizer 10.

The position shown in FIG. 5 is the locked position of theauto-adjusting mask stabilizer 10 and relative movement between thecushion frame 12 and the mask extension 14 is prevented, or locked, bythe engagement of the ratchet teeth 52 of the pawl 50 with the ratchetteeth 46 of the slot 45 or by high friction coefficient material on thepawl 50 and/or the ratchet teeth 52 to lock the movement, e.g. a clutch.

The biasing element 42 operates to bias the shaft 40 of the cushionframe 12 away from the cylinder 30 of the frame extension 14. When thelock mechanism is in the position shown in FIG. 5, movement of thecushion frame 12 caused by the biasing force of the biasing element 42away from the frame extension 14 is prevented by the engagement of theratchet teeth 52 with the ratchet teeth 46. In order to release the lockmechanism, the release button 32 is pressed downwardly to release theengagement of the ratchet teeth 52 from the ratchet teeth 46. When theratchet teeth are disengaged, the biasing element 42 biases the cushionframe 12 in a direction away from the frame extension 14 toward theforehead of the patient.

The engagement of the shaft 40 of the cushion frame 12 into the bore 36of the mask extension cylinder 30 allows the cushion frame 12 totranslate with respect to the mask frame 17. Thus, the inclinationbetween the cushion pads 25 and the patient's forehead does not changeduring adjustment, i.e., movement of the cushion frame 12 with respectto frame extension 14. The mask stabilizer 10 of the present inventionthus provides the ability to stabilize the vertical angle of theposition of the mask 16 relative to the patient's forehead and alsostabilizes the relative set position of the mask 16 throughout thepatient's sleep session.

Referring to FIG. 6, when the mask system is initially fitted, the shaft40 of the cushion frame 12 is fully inserted into the mask extensioncylinder 30. In this position, the biasing element 42 is undercompression and the forehead pads 25 are in the most outward setposition so that the compression of the biasing element 42 is at amaximum and the forehead pads 25 are at their closest position to theframe extension 14. In order to determine the ideal position of the mask16 on the patient's face, the mask 16 is placed in contact with thepatient's face and adjusted so that a good seal and comfortable fit areobtained. The lock mechanism release button 32 is then pressed down andthe engagement between the ratchet teeth 52 and the ratchet teeth 46 isreleased. The biasing element 42 then acts to bias the cushion frame 12toward the patient's forehead and into contact with the patient'sforehead. Once the forehead pads 25 are in contact with the patient'sforehead, the lock mechanism release button 32 is released and the lockmechanism returns to the locked position (i.e. the ratchet teeth 52 ofthe pawl 50 return to engagement with the ratchet teeth 46 of the slot45). Fine tuning of the fit may be achieved by repressing the releasebutton 32, which releases the lock mechanism, and moving the mask 16relative to the patient's face. Once the fine tuning is complete, therelease button 32 is again released and the lock mechanism returns tothe locked position to lock the cushion frame 12 into position.

The adjustment may be performed with one hand. The patient, or clinicworker, simply presses the release button 32 and adjusts the position ofthe mask 16 with the same hand used to depress the release button 32.This allows adjustment of the fit of the mask 16 according to thepresent invention in a quicker manner than mask systems of the priorart. A mask system including the auto-adjusting stabilizer according tothe invention may be initially fit in under one second, almostinstantaneously, as opposed to up to five seconds as may be required forforehead supports according to the prior art. As the mask adjustment maybe performed with one hand, the mask system of the present inventionrequires less dexterity to adjust than masks of the prior art.

As shown in FIG. 3, the biasing element 42 may be a coiled compressionspring. For example, the spring could be a stainless steel ornickel-plated spring. It should be appreciated, however, that thebiasing element 42 may take other forms. For example, the biasingelement 42 may be a compressible open cell foam or silicone rubberelastic band. As another example shown in FIG. 13, the biasing element42 may be an air spring having a reservoir, or an air bladder orintegrally spring-loaded bellows 42 a with an elastic memory so as theair is compressed the bladder can stretch and provide a spring force.The air bladder could be in communication with the air being deliveredto the mask so that an air line 60 is provided between the inside of themask frame and the air bladder or bellows 42 a so that the air bladderor bellows 42 a is under the influence of air pressure which influencesor biases the movement of the cushion frame 12 toward the patient'sface. It should also be appreciated that the air bladder may be providedwith a valve 62 allowing the deflation of the air bladder. In operation,the air bladder or bellows 42 a is normally in an extended position.Prior to fitting the mask to the patient, the valve 60 is opened and theair bladder or bellows 42 as is compressed during fitting. The valve 60is then closed to fix the support in position.

SECOND EMBODIMENT

Referring to FIG. 8, according to another embodiment of the invention, abushing 61 may be provided between the release button 32 and the outersurface of the mask extension cylinder 30. The bushing 61 serves toadjust the force required to depress the release button 32. The bushing61 may also serve to prevent accidental release of the lockingmechanism, for example during movement of the patient during the sleepsession. The bushing 61 may also bias the locking mechanism into thelocked position.

ALTERNATE EMBODIMENTS

Although the lock mechanism release button 32 is shown in the attacheddrawings as being provided on top of the mask frame extension cylinder30, it should be appreciated that the release button could also beprovided anywhere along the circumference of the mask frame extensioncylinder 30, with a corresponding movement of the slot 45 and ratchetteeth 46 of the shaft 40 of the cushion frame 12. It should also beappreciated that the release button could be provided at the closed endof the mask frame extension cylinder 30. However, positioning therelease button 32 on top of the frame extension cylinder 30 allows thepatient to activate the release button in a natural way and the forcethat is required to activate the release button is in a plane normal tothe direction along which the patient or fitter is positioning the mask.This minimizes the chance of moving the mask while adjusting theposition of the cushion frame 12.

Spacing of the ratchet teeth 46 in the slot 45 of the shaft 40 of thecushion frame 12 may be, for example, 1 mm The position of the cushionframe 12 may thus be adjusted in 1 mm increments. It should beappreciated, however, that other spacings of the ratchet teeth 46 arewithin the spirit and scope of the invention.

THIRD EMBODIMENT

Referring to FIG. 9, an auto-adjusting stabilizer according to anotherembodiment of the invention includes a frame extension 14 a having aframe extension cylinder 30 a. A shaft 40 a of a cushion frame (notshown) is received in the frame extension cylinder 30 a. A biasingelement (not shown) is provided between the cylinder 30 a and the shaft40 a to bias the shaft 40 a relative to the frame 30 a.

Radial projections 38 a of the frame extension cylinder 30 africtionally engage the outer surface of the shaft 40 a to retain theshaft 40 a against movement relative to the cylinder 30 a caused by thebiasing element. A lock mechanism release button 32 a is provided forreleasing the engagement of the radial projections 38 a from the shaft40 a to permit relative movement between the shaft 40 a and the cylinder30 a by the biasing element. Depressing the release button 32 a causesthe cylinder 30 a to deform, thus disengaging the projections 38 a fromthe cylinder 40 a.

FOURTH EMBODIMENT

As shown in FIG. 10, a lock mechanism 32 j according to an embodiment ofthe invention includes a lock mechanism release button 32 b engagable bythe patient or clinician. The release button 32 b is supported by arelease button support 32 c. The release button support 32 c includes acylindrical portion 32 d that receives a release mechanism sleeve 32 e.The sleeve 32 e is concentrically supported by the cylindrical portion32 d to permit relative movement between the release button support 32 cand the sleeve 32 e. Resilient, curved legs 32 f couple the support 32 cto the sleeve 32 e and a cylindrical plug 32 g connected to the releasebutton 32 b couples the release button 32 b to the support 32 c. Abiasing element 32 k, e.g., a spring, is provided between thecylindrical plug 32 g and a cross element 32 i in the sleeve 32 e tobias the lock mechanism 32 into the position shown in FIG. 10.Depressing the release button 32 b causes the plug 32 g to compress thebiasing element 32 k. The biasing element 32 k is initially compressedby movement of the release button 32 b, and then transfers furtherdepression of the release button 32 b to the sleeve 32 e throughengagement of the biasing element and the cross element 32 i.

FIFTH EMBODIMENT

The ratchet teeth of the lock mechanism shown in FIGS. 1-7 may bereplaced by a friction lock. Referring to FIGS. 11 and 12, the releasebutton 32 b of the lock release mechanism includes a pawl 50 b. The pawl50 b includes an engagement surface 53 on each side that engages acorresponding engagement surface 47 of the slot 45 b of the shaft 40 bof the cushion frame to lock the cushion frame in position. Theengagement surfaces 53 of the pawl 50 b and the engagement surfaces 47of the slot 45 b may be textured, such as by knurling, to increase thefriction between the pawl 50 b and the sides of the slot 45 b. The useof a friction lock would provide for continuous, or infinite,variability of the position of the cushion frame 12 with respect to themask 16. In contrast to prior art forehead supports which provide alarge number of discrete set points for the support and which may becomplicated to use and fit, the provision of an infinite number of setpoints simplifies using and fitting masks incorporating anauto-adjusting stabilizer according to the invention. Although FIGS. 11and 12 include a space between the engagement surfaces 47 and 53 forillustrative purposes, it should be appreciated that the surfaces are incontact.

The release button 32 b is biased into the locked position shown inFIGS. 11 and 12 by a biasing element 32 k, e.g., a spring. A projectingrim 41 b in the slot 45 b of the shaft 40 b engages a shoulder 33 b ofthe release button 32 b to maintain the release button 32 b in thelocked position shown in FIG. 11 When the release button 32 b isdepressed, as shown in FIG. 12, the amount of engagement between theengagement surfaces 47 and 53 is reduced and the amount of friction iscorrespondingly reduced. The shaft 40 b of the cushion frame is thenmovable relative to the mask extension cylinder that supports therelease button 32 b to permit adjustment of the position of the cushionframe.

SIXTH EMBODIMENT

Referring to FIGS. 14 and 15, according to another embodiment, thecushion frame 12 may include a flexible member 72 which has two side byside spaced apart tongues 74 and a middle protruding button 76 on itsdistal end. The frame extension 14 may include two generally arcuateshaped portions 78 that each have a pair of four grooves 80. It shouldbe appreciated that the pair of four grooves is merely an example andthat only two or more grooves are required. It should also beappreciated that the flexible member 72 can be on the frame extension 14and the grooves 40 can be on the cushion frame 12. The tongue 74 and thegrooves 80 extend in a direction substantially parallel to a lineextending radially from the axis 70. The cushion frame 12 may beconstructed from a plastic material, such as polypropylene orpolycarbonate, which allows the member 72 to be flexed relative to thecushion frame 12 upon which is mounted when pressure is applied to thebutton 76 in the direction of arrow 82. The corresponding movement ofthe tongues 74 releases them from engagement with one of the pairs ofgrooves 80 (as shown in FIG. 15) to allow angular adjustment between thecushion frame 12 and the joining member 14 about the axis 30. Releasingthe button 76 allows the tongue 74 to resiliently flex back towards thegrooves 80. When the tongues 74 and one of the pairs of grooves 80 arealigned (as shown in FIG. 14) the tongues 74 engage one of the pair ofgrooves 80. When the tongues 74 are engaged with one of the pair ofgrooves, the cushion frame 12 and joining member 14 are locked againstpivotal movement therebetween at a predetermined angle.

A biasing member, such as a torsion spring (not shown), may be providedbetween the cushion frame 12 and the mask extension 14 to bias thecushion frame 12 into a position when the button 76 is released. Forexample, the biasing member may be configured to bias the cushion frame12 toward the face of the patient when the button 76 is pressed.Alternatively, the biasing member may be configured to bias the cushionframe 12 away from the face of the patient when the button 76 ispressed.

The cushions 25 may be supported on the cushion frame 12 by a resilientmember 90. For example, the resilient member 90 may be a silicone rubberstem-like member. As the cushion frame 12 rotates about the axis 70, theresilient member 90 is able to flex or bend to maintain the contact faceof the cushion 25 flush against the face of the patient, e.g. againstthe patient's forehead.

It should be appreciated that the auto-adjusting mask stabilizer may beincorporated into any mask system where the fitting and correctadjustment of the mask relative to the wearer's head or face can beachieved. For example, the auto-adjusting mask stabilizer of theinvention may be used in mask systems that are not provided with aforehead support, but instead utilize, for example, a cheek support orupper lip support. It should further be appreciated that theauto-adjusting mask stabilizer of the invention may be utilized in amask system in which the forehead support is located or otherwiseattached to a headgear system. It should be even further appreciatedthat the auto-adjusting mask stabilizer may not include a lockmechanism. In such case, the cushion frame would be biased against thepatient's head, e.g., forehead, by the biasing element and its positionwould self-adjust to the patient.

While the invention has been described in connection with what arepresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiments, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the invention. Also, the various embodiments described abovemay be implemented in conjunction with other embodiments, e.g., aspectsof one embodiment may be combined with aspects of another embodiment torealize yet other embodiments. Further, each independent feature orcomponent of any given assembly may constitute an additional embodiment.Furthermore, each individual component of any given assembly, one ormore portions of an individual component of any given assembly, andvarious combinations of components from one or more embodiments mayinclude one or more ornamental design features. In addition, while theinvention has particular application to patients who suffer from OSA, itis to be appreciated that patients who suffer from other illnesses(e.g., congestive heart failure, diabetes, morbid obesity, stroke,barriatric surgery, etc.) can derive benefit from the above teachings.Moreover, the above teachings have applicability with patients andnon-patients alike in non-medical applications.

1-18. (canceled)
 19. A forehead support for a facial mask, the facialmask having a mask frame, the forehead support comprising: a frameextension provided on top of the mask frame, the frame extension havinga cylindrical extension; a cushion frame including a shaft received in abore of the cylindrical extension, the cushion frame being adapted to bemoveable between a first position with respect to the mask frame and asecond position with respect to the mask frame, the second positionbeing towards a wearer's forehead; and a compressible biasing elementprovided inside the shaft, the compressible biasing element beingconfigured to urge the forehead support towards the second position. 20.The forehead support according to claim 19, further comprising headgearconfigured to support the facial mask on a wearer's head.
 21. Theforehead support according to claim 20, wherein the cushion framefurther includes slotted connectors configured to be connected to endsof an upper head strap of the headgear.
 22. The forehead supportaccording to claim 19, wherein the shaft is translatably supported inthe cylindrical extension.
 23. The forehead support according to claim19, wherein the compressible biasing element is configured to bias theshaft away from the cylindrical extension.
 24. The forehead supportaccording to claim 19, further comprising at least one forehead padsupported by the cushion frame.
 25. The forehead support according toclaim 19, wherein the compressible biasing element comprises acompression spring.
 26. The forehead support according to claim 19,wherein the compressible biasing element comprises an elastomeric springelement.
 27. The forehead support according to claim 19, wherein aninclination angle between the forehead support and the mask frameremains constant as the forehead support moves with respect to the maskframe.
 28. The forehead support according to claim 19, wherein theforehead support is configured to be adjacent and above a wearer's nose.29. The forehead support according to claim 19, wherein an axis of thecylindrical extension intersects the wearer's forehead.
 30. The foreheadsupport according to claim 19 further comprising a lock mechanismconfigured to lock the cushion frame in a position relative to the frameextension.
 31. The forehead support according to claim 19 furthercomprising: headgear configured to support the facial mask on a wearer'shead; at least one forehead pad supported by the cushion frame; and alock mechanism configured to lock the cushion frame in a positionrelative to the frame extension, wherein the cushion frame furtherincludes slotted connectors configured to be connected to ends of anupper head strap of the headgear, wherein the shaft is translatablysupported in the cylindrical extension, wherein the compressible biasingelement is configured to bias the shaft away from the cylindricalextension, wherein the compressible biasing element comprises acompression spring, wherein the compressible biasing element comprisesan elastomeric spring element, wherein an inclination angle between theforehead support and the mask frame remains constant as the foreheadsupport moves with respect to the mask frame wherein the foreheadsupport is configured to be adjacent and above a wearer's nose, andwherein an axis of the cylindrical extension intersects the wearer'sforehead.
 32. A mask for positive airway pressure therapy comprising: aframe; and the forehead support of claim 19, the forehead supportextending from the frame.
 33. A mask for positive airway pressuretherapy comprising: a mask frame; a frame extension provided on top ofthe mask frame, the frame extension having a cylindrical extension; anda forehead support moveable between a first position with respect to themask frame and a second position with respect to the mask frame, thesecond position being towards a wearer's forehead, the forehead supportcomprising: a cushion frame including a shaft received in a bore of thecylindrical extension; and a compressible biasing element providedinside the shaft, the compressible biasing element being configured tourge the forehead support towards the second position.
 34. The maskaccording to claim 33, wherein the mask further comprises: a maskcushion supported by the mask frame; an angled connector with a distalend configured to connect to a gas supply hose and a proximal endconfigured to connect to the mask; and headgear configured to secure themask to a wearer's head.
 35. The mask according to claim 34, wherein theangled connector comprises a swivel elbow.
 36. The mask according toclaim 34, wherein the mask frame includes a pair of connectorsconfigured to connect to a lower strap of the headgear.
 37. A foreheadsupport for a facial mask, the facial mask having a mask frame, theforehead support comprising: a frame extension with a proximal endadjacent the mask frame and a distal end opposite the proximal end; abore positioned at the distal end of the frame extension; a shaft thatis received through the bore and is movable through the bore, the shaftbeing oriented so that a longitudinal axis of the shaft is transverse tothe longitudinal axis of the frame extension; and a cushion framepositioned at an end of the shaft so that the cushion frame is movablewith the shaft toward and away from the bore along the longitudinal axisof the shaft, wherein the cushion frame is configured to be selectivelyfixed at a plurality of discrete distances from the bore.
 38. Theforehead support according to claim 37, wherein the bore is orientedrelative to the frame extension so that a longitudinal axis of the frameextension is transverse to a central axis of the bore.
 39. The foreheadsupport according to claim 37, wherein the shaft is translatablysupported in the bore.
 40. The forehead support according to claim 37further comprising at least one forehead pad supported by the cushionframe.
 41. The forehead support according to claim 37, wherein aninclination angle between the shaft and the mask frame remains constantas the shaft moves through the bore.
 42. The forehead support of claim37, wherein the shaft is biased to urge the cushion frame away from thebore.
 43. The forehead support of claim 38, wherein the shaft is biasedby a compressible biasing element inside the shaft.
 44. A mask forpositive airway pressure therapy comprising: a cushion configured tosealingly engage a patient's face; a frame that forms a chamber with thecushion; the forehead support of claim 37, the forehead supportextending from the frame; and headgear that is attachable to theforehead support and the frame.
 45. The mask of claim 44, whereinposterior opening in the cushion and an anterior opening in the frameare coaxial along a longitudinal axis that is transverse to thelongitudinal axis of the frame extension of the forehead support.